Set Deduplication/Compression Mode

Overview

This function enables or disables the Deduplication/Compression function for the storage system.

If the Deduplication/Compression function is enabled, the duplicated data blocks in TPP are deleted and compressed to reduce the used area of the drive.

Caution

  • The ETERNUS DX900 S6 or the ETERNUS DX8900 S6 support the Compression function only.

  • If this function is enabled, the performance may be reduced depending on the I/O environment. For notes on using this function, refer to "Design Guide".

  • Only Deduplication/Compression Volumes in the same TPP are the targets of Deduplication/Compression. TPVs that are not Deduplication/Compression Volumes are not supported.

  • Checking for duplications across multiple TPPs is not supported.

  • When this function is enabled, the cache mode is temporarily changed to "Write Through Mode". The workload I/O performance of the entire storage system is lowered when the cache mode is transitioning to "Write Through Mode". Therefore, it is recommended to use this function when work I/O is low. This process may take up to several tens of minutes.

  • If this function is changed from "Enable" to "Disable", reboot the storage system. Note that rebooting the storage system is not required if this function is changed from "Disable" to "Enable".

  • If the Deduplication/Compression Volume is used as a copy source volume, the copy process is performed after the data is decompressed. If the Deduplication/Compression Volume is used as a copy destination volume, the data that is transferred from the copy source is deduplicated and compressed. Because of that, the copy performance is affected.

  • This function cannot be disabled under the following conditions:

    • TPPs that have either or both of Deduplication and Compression enabled exist

    • The current user does not have the "Maintenance Operation" policy

Note

  • Check "Deduplication/Compression" in the [System] screen. If "Enable" is displayed for "Deduplication/Compression", skip this function. Refer to the [System] function for details.

Configuration procedure for the Deduplication/Compression function

  1. Use this function to enable Deduplication/Compression for the storage system.

  2. Enable the Thin Provisioning function and then select the maximum pool capacity. Refer to the [Set Thin Provisioning] function for details.

  3. Create a TPP with "Deduplication", "Compression", or both of them enabled. Refer to the [Create Thin Provisioning Pool] function for details.

    (A Data Container Volume is automatically created in the relevant TPP.)

  4. Expand the logical capacity of the Data Container Volume.

    The logical capacity of the Data Container Volume must be expanded to a size that is the same or larger than the capacity that is to be written. This is because the data for all Deduplication/Compression Volumes in the TPP is written to the Data Container Volume after the Deduplication/Compression.

    If the capacity that is to be written cannot be estimated, expand the logical capacity of the Data Container Volume to the same or larger than the total logical capacity of all Deduplication/Compression Volumes in the TPP.

    Examples of when creating ten 10 TB Deduplication/Compression Volumes in a TPP are as follows.

    • When the estimated data reduction rate is 2:1, expand the Data Container Volume capacity to 50 TB

    • When the estimated data reduction rate is 4:1, expand the Data Container Volume capacity to 25 TB

    Refer to the [Expand Thin Provisioning Volume] function for details.

  5. Create the Deduplication/Compression Volumes in the TPP that was created in Step 3. Refer to the [Create Volume] function for details.

Settings

Deduplication/Compression Mode Settings

Item Description Setting values

Deduplication/Compression

Select whether to enable or disable the Deduplication/Compression function for the storage system.

The display contents vary depending on the current user's policy.

  • When the user has the "Storage Management" policy

    Enable

  • When the user has the "Maintenance Operation" policy

    When the Deduplication/Compression function of the storage system is enabled

    Enable

    Disable (Default)

    When the Deduplication/Compression function of the storage system is disabled

    Enable (Default)

    Disable

Operating Procedures

  1. Click [Set Deduplication/Compression Mode] in [Action].

  2. Select whether to enable or disable Deduplication/Compression and click the [Set] button.

    → A confirmation screen appears.

  3. Click the [OK] button.

    → The Deduplication/Compression mode setting starts.

  4. Click the [Done] button to return to the [System] screen.

    Caution

    • Reboot the storage system if "Disable" is selected for "Deduplication/Compression".